Dual clutch transmissions for the actuation of motor vehicles, which comprise two sub-transmissions, which in each case have a main clutch, are known from the technical field. The aforementioned main clutches are actuated by means of hydraulic actuating elements. Aside from these, clutches are known, which are actuated by means of electrical actuators, as for example electric motors, and suitable kinematics assigned to said actuators. A clutch is in each case actuated by a motor with an assigned kinematics, which is appropriately designed, independently of the other one.
With regard to clutches actuated by means of electric motors, the electric motors are constantly supplied with current not only for closing the clutches but also for keeping them closed. The result is that the electric motors have to be adequately sized and the power electronics have to meet the required demands. With regard to clutches, which are controlled by an electric motor, it must be ensured that each of the two clutches of the dual clutch transmission can in each case be completely closed by an electric motor independently of each other. For this purpose, each of the two available electric motors has to produce the maximum closing force, which requires adequately powerful and therefore expensive electric motors. If an error occurs, both of the clutches open, which in each case are driven by an electric motor, so that the drag torque of the internal combustion engine is no longer available and the engine brake is ineffective. Thus, on the one hand a blocking of the transmission is prevented; however, on the other hand, the engine brake is ineffective.
The European patent EP 1 178 234 B1 refers to a clutch arrangement. The clutch arrangement serves to transmit a torque from the drive shaft to an output shaft with a first coupling element and a second coupling element. The first coupling element is connected to the drive shaft and the second coupling element to the output shaft. Provision is made for an actuator, which specifies a nominal value for a torque to be transmitted with the clutch, as well as for an adjusting device, which uses the rotational power of the drive shaft for engaging and/or disengaging the coupling elements. The engaging and/or disengaging of the coupling elements results via a bevel toothed gear. The adjusting device is directly connected to the drive shaft and uses its rotational power squarely for positioning the coupling elements. In so doing, the actuating energy for the adjusting device, which is required for actuating the clutch arrangement, can be directly drawn from the drive train, respectively the drive shaft. The energy drawn from the drive train for an actuation of the clutch arrangement via the adjusting device is not initially used for driving an electric motor, an electric magnet or a hydraulic cylinder. On the contrary, the energy of the drive train is directly supplied without conversion to the adjusting device in order to actuate the clutch arrangement.